The usual conventional skateboards use four small diameter wheels positioned beneath the board on which the rider stands. The wheels are made of a solid material that provides no shock absorption. The board is propelled by the rider by kicking one foot on the ground. Steering is accomplished by shifting the rider's weight to tilt the board. The limitation of this version is that the small diameter wheels can only be used on smooth surfaces that are free of debris.
New types of skateboards have been proposed over the years to overcome the limitations of the small wheels by creating skateboards with large diameter wheels and pneumatic tires. However, these boards cannot be easily propelled by the rider. The large wheel boards have higher riding platforms which makes the boards unstable, difficult to ride, and potentially unsafe to the rider. Most of these other types of boards are propelled only by gravity and thus require a sloping surface for any use.
U.S. Pat. No. 6,398,237 to Attey describes a skateboard that utilizes two in-line large diameter wheels where a single front wheel pivots to accommodate steering. Similar to a bicycle, with only two wheels this device can only remain vertical while in motion. A rider would not be able to remove one foot from the device for propulsion without losing stability and falling off the board.
U.S. Pat. No. 5,794,955 to Flynn describes a mountain board that requires four large diameter wheels which are mounted on wide axles that extend beyond the width of the board. The two wheels at the rear of the board can cause interference for the rider should the rider attempt to propel the board by kicking one foot.
U.S. Pat. No. 5,100,161 to Tillyer; U.S. Pat. No. 5,997,018 to Lee; U.S. Pat. No. 5,645,291 to Ramage; and U.S. Pat. No. 5,474,314 to Lehman also each require four large wheels located beneath the board that results in a high riding platform, or ‘deck,’ which makes these devices cumbersome and difficult to operate.
U.S. Pat. No. 5,551,717 to Milne has two front wheels that steer and a single rear wheel; however, this device is much less stable. Milne's design includes a deck that is mounted to the frame via longitudinal pivot points beneath the deck. This allows the deck to tilt from side to side while the frame remains level. Steering linkage components connected to the deck turn the front wheels when the deck is tilted. The deck is higher than the axles of the wheels. The combination of the high deck and the pivot point located below the plane in which the rider stands makes this unstable. Additionally, the Milne's device appears to be limited for off-road use only and may further be limited to use on sloping surfaces.
Thus, the need exists for solutions to the above problems with the prior art.